My stay at the Riverside Studio was really nice, and very relaxing being by the river. This place has everything you need and more.. the Big C is close by and the café at the complex was really cheap and the food was great.
You can take a local bus no. 6 to pepsi pier which costs 9 baht or 13 baht if it has A/C. Then take the local ferry for 5 baht over the river where the BTS Station is also you can take a local boat down the river for 15 baht.
You can get a massage at the Big C for only 150 baht, this area is really nice as you feel like you are amongst the locals and not a tourist.
The pool, sauna and gym are also very nice. I found it to be cooler also being by the river. The complex has a boat that you can take for 35 baht to the BTS in the morning and in the evenings and they also have a shuttle bus.
I highly recommend this place to relax and enjoy Bangkok.